Preparation of unsaturated cyclic



PREPARATION OF UNSATURATED CYCLIC I UREA DERIVATIVES Robert S. Yost, Oreland, Pa., assignor to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware Application December 11, 1 956 Serial No. 627,572 1 15 Claims. (C. 260-251) No Drawing.

This invention relates toa new and improved process 2,880,208 Patented Mar. 31, 1959 added, such as sulfuric, hydrochloric, acetic, oxalic,

and so on. While the proportions between the reactants II and III may vary, it is preferable to use between 1 and 2 moles of the aldehyde of Formula II for each mole of the cyclic urea of Formula III. The amount of sol- I vent that may be used may vary widely, but for practical purposes it is preferred that the reaction be carried out in a fairly concentrated solution. It is generally desirable to add one "of the reactants or a solution thereof to the other reactant or to a solution of the other. For ex- L ample, the aldehyde may be added to an aqueous solufor the production of N-vinyl-2-imidazolidinones and the N-vinyl-tetrahydro-2-pyrimidinones. These compounds are sometimes called vinyl ethyleneureas vor vinyl trimethyleneureas. This application is a continuation-inpart of my copending application Serial No. 567,064, filed February 23, 1956, now abandoned.

Compounds prepared in accordance with the new process of the present invention have the structure of Formula I:

1 o it where 'R is selected from the group consisting of 'H, phenyl, tolyl, benzyl, cyclohexyl and alkyl groups having 1 to 8 carbon atoms, and .R is selected from the group consisting of H and alkyl groups having 1 to 4 carbon atoms, and n is an integer having a value of 1 to 2.

In accordance with the present method for producing these compounds, an aldehyde of Formula II is reacted with a compound of Formula III:

mixing the two reactants together in the. presence of acid or mixing the reactants and then adding a small amount of acid or mixing the reactants under such conditions that a small amount of acid is developed as by oxidation of a part of the aldehyde effected in a solvent for the reactants. The solvent is preferably water, but

instead there may be used such lower alcohols as methi anol, ethanol, and isopropanol. When water is used as the solvent, the condensation of compounds II and III is effected onthe acid side at a pH of less than 7,'such as from a pH between 1 and 5 orbetween 3.5 and 4.5,

tion of the cyclic urea, the addition being made gradually over a'period of time. The temperature may vary from 15 to 220 C., depending upon the boiling point of either of the reactants or the solvent. Preferably, organic acids are employed and frequently the aldehyde may contain sufficient organic acid as an impurity to provideall the acid that is necessary. In many cases, it may be desirable to cool one or both of the reactants or their solutions before mixing them. For example, the aldehyde or its solution may be cooled to 15 or 20 C. or even somewhat lower before it is added to the solution of the cyclic urea which may be at a temperature of 25 to 30 C., at room temperature or even at a temperature therebelow. After the addition of the aldehyde to the cyclic urea, it may be necessary to provide additional cooling to prevent volatilization of either of the reactants or of the solvent, depending upon the conf centration and the rate of addition which, of course, infiuen'ces the extent to which the temperature is raised.

Themixing' of the reactants,"such as by the addition of the aldehyde to a cyclic urea solution may be effected very quickly as in a period of a few minutes or it may take a period of as much as three-quarters of an hour to an hour or more. After the addition has beencompleted,

' r the mixture is allowed to stand with heating or cooling or without either heating or cooling until 90% to '100% of the aldehyde has reacted with the cyclic urea, which may readily be determinedby titrating in accordance with the sulfite method of detecting an aldehyde. After substantial completion of the reaction, the acid may be neutralized, but if only a small quantity of acid is pres ent, such neutralization may not be needed. Neutralization, if employed, may involve adjustment of the pHto 7 to 8; that is, to approximate neutrality with a base,

such as a solution of caustic soda, caustic potash or the like.

Thereafter, the water and any unreacted aldehyde or aldol-condensation by-prodncts are removed by distilling in a vacuum... Generally, the distillation may be effected at a temperature of the batch between and and'preferably between 6.0 and. 6.5. .To obtain the 3 pH desired, a small amount of any suitable acid may be C. It is preferable to keep the batch hot while distilling, such, as at a temperature of at least 50 C. to avoid the development of excessive viscosity which would render agitation and heat-transfer into the batch rather dilficult.

By the reaction between Compounds II and III, a compound of Formula IV is believed tobe obtained in ac -cordance-with Equation A following:

- EQUATION A o o H II RR'CHCHO +HN \NH rm N-omorncrran' H20 011, H: /CH9 CH2) n: do H2) n l (II) (III) (IV) 'The compound of Formula IV obtained by Equation A is believed to condense with itself to produce a polymer. (V) in accordance with Equation B following:

3 4 EQUATION B and caught in a separate fraction, which is followed by R the distillation of the desired product under high vacuum ll l at temperatures of 185 to 285 or 300 C. Where crack- N v mg to produce a compound of Formula I occurs. The I H I product of formula I may be isolated from the last frac- 11,0 H tion distilled in the same manner as described herein- (0 2)! (IV) Additional monovmyl cyclic urea is obtained by adding a small amount, such as 1% to 5%, based on the weight 6 of the alkoxyalkyl cyclic urea, of an alkali metal alkoxide, O HCR such as sodium methoxide or sodium ethoxide, to the H OH 1)H2O fraction containing the a-alkoxyalkyl and bis-a-alkoxy- 1 l alkyl cyclic ureas of Formulas VI and VII. Fractional distillation in the presence of these alkoxides converts (CH2)n-l z 5 the a-alkoxyalkyl cyclic urea of Formula VI to the N- (v) mono-alkenyl cyclic urea product, such as the N-vinyl After unreacted aldehyde, water, and by-products have eyehe urea e which may be Collectedbeen stripped, the heating in vacuum is continued through n the fellowmg examples e e and Pereentages temperatures of at least 185 C. up to 285 to 300 C. are by we ght unless otherwise indicated. When spotwhile gradually increasing the vacuum to distill as much Plate 1 1s referred to in the alcoholic systems it is f tha product having Formula I as is possible The determined by adding a drop of the alcoholic system to product. f Formula 1 appears to be obtained as a result a drop of an aqueous solution of an Indicator, such as f the cracking f the compound of Formula v which brom-cresol green when the pH is in the range of about appears to occulat temperatures f 3 to 5 4 to 5 and brom-thymol blue when the pH is about 6 to The distillate contains the product of Formula I and may contain unreacted cyclic urea. The product of Example 1 Formula I is recovered from the distillate by heating it and agitating it in the presence of a solvent for the solution of methyl hemiacetal was prepared by product, such as toluene, xylene, ethyl, acetate, acetone, addmg 88 Parts of freshly'dlsnned acetaldehyde to 1 or ether, which extracts the product. Generally, any e of ashydrous rilethaml over a penod of common organic solvent except alcohols and aliphatic mljlutes whlle mamtammg the temperature at 25 to hydrocarbons may be employed as the extracting solvent. 30 This extraction may be effected while refluxing the solvent 'ethyleneurea (172 Parts) was dlssolved 200 to prevent its loss. The insoluble cyclic urea is filtered Parts of methanol and 6 Parts of 73% meihanohc off leaving the product dissolved in solvent as obtained ehlende was added" The methyl hemlacetal (zfis in the filtrate. The solvent is then stripped off by distilla- Parts) was then added over aopenod f one hour while tion and further purification may be effected either by holdms the tempefamre s 30 to The mixture distillation or recrystallization of the product from anwas a'gltated at 32 to 34 fer thlrty mmuotes and then other solution in a solvent, such as by chilling it. allowed to stand. at e tempereture (28 over When an alcohol is used as the solvent, the reaction 40 night Methanol: sodlum methexlde (3 parts of 254% between Compounds II and II is etfected in a similar solution) was added the e e and water striliped manner, the same amount of acid being added as would Y The resldPe was elstlned thru a modeled be needed to. produce the desired pH of not over 7 if eP apparatus to Yleld freshen A (92's Parts) l' water were used as the solvent. For this purpose, a a bolhng range from at Hg to s methanolic hydrogen chloride may be used. In the case eg; and ffactlon B (115 parts) having a of using an alcohol as the solvent, and especially when bollmg range from at m g t0 acetaldehyde is used, an walkoxyalkyl cyclic urea of at latter frflctlon was formed y Formula VI and a bis-(a-alkoxyalkyl) cyclic urea of fi g a falrly viscous, reslnous material. f ul v11 may be obtained as byproducts, apparently so Fraction A was redistilled to yield fraction A-1 (16.5 as a result of the process represented by Equations C P bolllng at to at Flactloll and A-2 (14.6 parts) boiling at 86 to 103 C. at 0.65 mm. EQUATION C Hg; and fraction A-3 (37.5 parts) boiling at 103 to e H 114 C. at 0.75 mm. On the basis of methoxyl group .RB'CHGHO'+ R 011 ,RR'CHCOR and nitrogen analyses, the compositions of the three fractions were as follows: (11) Fraction A-1: Where 18 the alkYl gmuP the 83% N,N'-bis[oa-methoxyethyl]-N,N-ethyleneurea EQUATION D 17% N-ia-methoxyethyll-N,N-ethyleneurea O O 'O H II II c H H H H HN/ \NH 3(RR'VCH8OR) 'HN/ NUSCHRR'. RR'HCg-N N--8CHRR 31120 H: OH: H H2O (13H: R3 R H2O OH: R3

C a): (CH2)n-l CHl)n-l (111) VI) (VII) The weight of the a-alkoxyalkyl cyclic urea of For- Fraction A-2:

mula VI may amount to 30% of the total reaction product. Generally, a polymer of Formula V constitutes about 40% of the reaction productand about 7% to 10% of the reaction product is a bis-Malkoxyalkyl cyclic urea of Formula VII above. The alcohol is stripped off along with any residual aldehyde. Then-the a-alkoxy- 41% N,N-bis a-methoxyethyl] -N,N-ethyleneurea 59% N-[u-methoxyethyl]-N,N-ethyleneurea Fraction A-3:

' 85 N- a-methoxyethyl] -N,N'-ethyleneurca 15% N-vinyl-N,N'-ethyleneurea Fraction B was redistilled to yield fraction 13-1 (78.6

alkyl and bis-a-alkoxyalkyl cyclic ureas are distilled ofi parts) boiling at 113 to 121 C. at 0.4 mm.; and traction B 2 (12.6 parts) boiling at 124 C. at 0.38 mm. to 146 C. at 0.52 mm. Fraction B-2 was found by analysis to be N,N-ethyleneurea and fraction B-1 to consist of 83% N-vinyl-N,N'-ethyleneurea and 17% N-[a-methoxy- .ethyl]-N,N-ethyleneurea. The N-vinyl ethyleneurea was Example 2 N,N'-ethyleneurea (172 parts) was dissolved in 500 parts of isopropyl alcohol by warming to 50 C. The acidity of the solution was adjusted with methanolic hydrogen chloride to a spot-plate pH of 4.0 to 4.4, the solution was cooled to 30 to 40 C. and 88 parts of freshly distilled acetaldehyde was added over a period of thirty-five minutes while maintaining a temperature of 34 to 40 C. The mixture was allowed to stand at room temperature overnight. A solid by-product that had separated during this period was filtered off and the filtrate was adjusted to a spot-plate pH of 7.2 to 7.4 with methanolic sodium hydroxide. The alcohol was stripped in .vacuo and the residue distilled through a modified Claisen apparatus to yield fraction A (25.5 parts) boiling at 106 to 131 C. at 0.9 mm.; fraction B (67 parts) boiling at 131 to 154 C. at 1.5 mm.; and fraction C (31 parts)boiling at 148 to 154 C. at 1.5

\ mm. N-vinyl-N,Nethyleneurea (57.3 parts) (M.P.- 77

A43 and distillation produces a distillate containing N- vinyl-N,N'-ethy1eneurea.

Example 3 N,N'-ethyleneurea (172 parts) was dissolved in 400- parts of water. The pH was adjusted to 4.0 to 4.4 with hydrochloric acid and 123.3 parts of freshly distilled acetaldehyde was added over a period of one hour while holding the temperature at 25 to 30 C. The mixture was stirred for forty-five minutes at room temperature followed by adjustment of the pH to 7.3 to 7.5 with sodium hydroxide. The water was stripped off in vacuo and the residue was heated in vacuo to a maximum temperature of 239 C. During this period, the following fractions were distilled and collected. Fraction I(11.3 parts) boiling at 149 to 156 C. at 1.7 mm. Hg; fraction II (89.5 parts) boiling at 147 to 156 C. at 1.7 mm. Hg; and fraction III (76.8 parts) boiling at 146 to 147 C. at 1.2 mm. Hg. The three fractions were boiled with ether to extract the product from any N,N'- ethyleneurea present. N,N-ethyleneurea (22 parts) was recovered by filtration. Chilling of the ether filtrates precipitated N-vinyl-N,N-ethyleneurea (111 parts total), M.P. 71 to 73 C. Recrystallization of the latter from a methanol-ether mixture yielded 84 parts of N-vinyl- N,N-ethyleneurea, M.P. 76 to 78 C.

The filtrate from the original N-vinyl-N,N'-ethyleneurea precipitation was combined with that from the recrystallization, the ether evaporated-and the residue disoil in vacuo.

tilled to yield fraction IV (28 parts) boiling at 113 to 120 C. at 0.65 mm. Hg; fraction V (6.7 parts) boiling at- 120 to 131 C. at 0.65 mm. Hg; and fraction V1 (7.2 parts) boiling at 131 to 148 C. at 0.7 mm. Hg. Treatment of the fractions with ether as described above yielded an additional 25.7 parts of N-vinyl-N,N'-ethyleneurea (M.P. 77 to 78 C.) and 6.7 parts of N,N- ethyleneurea.

Example 4 The procedure of Example 3 was'repeated using 88 parts of acetaldehyde, instead of 123.3 parts, to yield 88.4 parts of N-vinyl-N,N'-ethyleneurea. N,N-ethy1- eneurea (44.7 parts) was recovered.

Example 5 N,N'-ethyleneurea (86 parts) was dissolved in 200 parts of water. The pH was adjusted to 4.2 to 4.4 with hydrochloric acid and 81.3 parts of propionaldehyde was added over a period of forty-five minutes while maintaining the temperature at 25 to 30 C. The mixture was then stirred at room temperature for forty five minutes, the pH was adjusted to 7.2 to 7.4 with sodium hydroxide and the water was stripped, in vacuo, leaving a clear viscous, resin-like mass. This resin was heated in vacuo to a maximum temperature of 225 C. During the heating period, distillation took place to give 97.6 parts of N-propenyl-N,N-ethyleneurea boiling at 153. to 161 C. at 1.6 to 2.0 mm. Hg. The product crystallized on standing and recrystallization from methanol gave the pure compound melting at 123 to 124 C.

Analysis.-Calcd for C H ON C, 57.12%; H, 7.99%; N, 22.21%; M.W. 126. Found: C, 56.86%; H, 8.02%; N, 21.89%; M.W. 129.

Example 6- N,N'-ethyleneurea 172 parts) was dissolved in 200 parts of water and 96.8 parts of freshly-distilled acetaldehyde was added over a period of thirty-five minutes while holding the temperature at 27 to 30 C. The mixture was stirred at room temperature for an additional thirty minutes after which the pH of the mixture was found to be 6.5. Sodium hydroxide was added to raise the pH to 8.0 to 8.2 and the water was stripped The residue was heated in vacuo to a maximum temperature of 275 C. During this period, distillate boiling at 156 to 166 C. at 0.4 to 0.8 mm. of mercury was collected. A mixture of the distillate (188 parts) and 630 parts of ethyl acetate was heated to boiling and then was chiled in an ice-bath. N,N'-ethyleneurea (25 parts) separated and was filtered off. The ethyl acetate was stripped from the filtrate in vacuo and the residue was distilled through a short Vigreux column to yield. 109.5 parts of N-vinyl-N,N'-ethyleneurea boiling at 114 to 117 C. at 0.5 mm. of mercury and melting at 77 to 79 C.

Example 7 (a) A mixture of 86 parts of N,N'-ethyleneurea.and 88 parts of freshly-distilled acetaldehyde was heated to reflux and maintained there until the ethyleneurea was completely dissolved. The mixture was then distilled in vacuo to yield 88.5 parts of distillate boiling at 147; to 163- C. at 1 mm. of mercury. A mixture of the distillate and 320 parts of ethyl acetate was heated to boiling and then was chilled in an ice-bath. N, N'-ethyleneurea.( 10 parts) separated and was filtered off. The ethyl acetate was stripped from the filtrate in vacuo and the residue was distilled through a short Vigreux column to yield 53.5 parts of N-vinyl-N,N-ethyleneurea boiling at 111 (c) The procedure of Example 7(a) was repeated substituting 134 parts of hydrocinnamaldheyde, to which 0.3 part of glacial acetic acid had been added, for the acetaldehyde to yield 90 parts of N-( 8-benzylvinyl)-N,N'- ethyleneurea.

(d) The procedure of Example 7(a) was repeated substituting 100 parts of N,Ntrimethyleneurea for the N,N'- ethyleneurea there used. The product (75 parts) was N-vinyl-N,N-trimethyleneurea.

(e) A yield of 100 parts of N-(fi-phenylvinyl)-N,N- trimethyleneurea was obtained by substituting 100 parts of N,N'-trimethyleneurea for the N,N'-ethyleneurea and 120 parts of phenylacetaldehyde for the acetaldehyde in the procedure of Example 7(a).

(f) A yield of 78 parts of N-(B-octylvinyl)-N,N- trimethyleneurea was obtained by substituting 100 parts of N,N'-trimethyleneurea for the N,N-ethyleneurea and 156 parts of capric aldehyde for the acetaldehyde in the procedure of Example 7 (a).

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A method for producing an N-vinyl derivative of a cyclic N,N'-alkyleneurea which comprises reacting, in the presence of an acid, an aldheyde having the structure of Formula II:

II RR'CHCHO and a cyclic urea having the structure of Formula III:

EN I -IH H26 CH2 where R is selected from the group consisting of H, phenyl, benzyl, cyclohexyl and alkyl groups having 1 to 8 carbon atoms, and R is selected from the group consisting of H and alkyl groups having 1 to 4 carbon atoms, and n is an integer having a value of 1 to 2, subsequently heating the reaction mixture to distill a product having the structure of Formula I:

0 II C HN/ \N-CH==GRR H2O CH2 CH2)n-l where R, R, and n are as defined above.

2. A method for producing N-vinyl-N,N-ethyleneurea which comprises reacting acetaldehyde and N,N-ethyleneurea in the presence of a small amount of acid, subsequently heating the reaction mixture to a temperature between 185 and 285 C. and distilling N-vinyl-N,N- ethyleneurea.

3. A method for producing an N-vinyl derivative of a cyclic N,N-alkyleneurea which comprises reacting, in an aqueous acidic solution having a pH less than 7., an aldehyde of Formula II as defined in claim 1 with a cyclic urea of Formula III as defined in claim 1, and subsequently heating the reaction mixture to distill a product having the structure of Formula I as defined in claim 1.

4. A method for producing an N-vinyl derivative of a cyclic N,N'-alkyleneurea which comprises reacting, in an aqueous acidic solution having a pH less than 7, an aldehyde of Formula II as defined in claim 1 with a cyclic urea of Formula III as defined in claim 1, adding an alkaline material to adjust the pH to a value of about 7 to about 8, and subsequently heating the reaction mixture to distill a product having the structure of Formula I as defined in claim 1.

5. A method for producing an N-vinyl derivative of a cyclic N,N'-alkyleneurea which comprises reacting, in an aqueous acidic solution having a pH between 1 and 6.5, an aldehyde of Formula II as defined in claim 1 with a cyclic urea of Formula III as defined in claim 1, adding an alkaline material to adjust the pH to a value of about 7 to about 8, subsequently heating the reaction mixture to a temperature between and 285 C., and then recovering a product of Formula I as defined in claim 1.

6. A method for producing N-vinyl-N,N'-ethyleneurea which comprises reacting, in an aqueous acidic medium having a pH between 1 and 6.5, acetaldehyde and N,N'- ethyleneurea, adding an alkaline material to adjust the pH to between about 7 and 8, subsequently heating the reaction mixture to a temperature between 185 and 285 C. and distilling N-vinyl-N,N'-ethyleneurea.

7. A method for producing an N-vinyl derivative of a cyclic N,N-alkyleneurea which comprises reacting, in an acidic solution in a lower alcohol, an aldehyde of Formula II as defined in claim 1 and a cyclic urea of Formula III as defined in claim 1, adding an alkaline material to adjust the pH to a value of about 7 to about 8, subsequently heating the reaction mixture to distill a product having the structure of Formula I as defined in claim 1.

8. A method for producing an N-vinyl derivative of a cyclic N,N-alkyleneurea which comprises reacting, in an acidic solution in a lower alcohol, an aldehyde of Formula II as defined in claim 1 and a cyclic urea of Formula III as defined in claim 1, adding an alkaline material to adjust the pH to a value of about 7 to about 8, distilling from the alkaline mixture a fraction containing an N-aalkoxyalkyl-N,N-alkyleneurea, adding a small amount of an alkali metal alkoxide to said fraction, and distilling the resulting mixture to produce a distillate containing a compound of Formula I as defined in claim 1.

9. A method for producing N-vinyl-N,N'-ethyleneurea which comprises reacting, in an acidic methanol solution having a pH between 1 and 6.5, acetaldehyde and N,N'- etnyleneurea, adding an alkaline material to adjust the pH to between about 7 and 8, subsequently heating the reaction mixture to a temperature between 185 and 285 C. and distilling N-vinyl-N,N'-ethyleneurea.

10. A method for producing N-propenyl-N,N-ethyleneurea which comprises reacting, in an aqueous acidic medium having a pH between 1 and 5, propionaldehyde and N,N-ethyleneurea, adding an alkaline material to adjust the pH to between about 7 and 8, subsequently heating the reaction mixture to a temperature between 185 and 285 C., and distilling N-propenyl-N,N'-ethyleneurea.

11. A method which comprises reacting hexahydrophenyl acetaldehyde and N,N-ethyleneurea at a temperature betwen 15 and 220 C., in the presence of acid, and subsequently distilling N (p-cyclohexylvinyl)-N,N-ethyleneurea.

12. A method which comprises reacting hydrocinnamaldehyde and N,Nethyleneurea at a temperature between 15 and 222 C., in the presence of acid, and subsequently distilling N-(B-benzylvinyl)-N,N-ethyleneurea.

13. A method which comprises reacting acetaldehyde and N,Ntrirnethyleneurea at a temperature betwen 15 and 220 C., in the presence of acid, and subsequently distilling N-vinyl-N,N'-trimethyleneurea.

14. A method which comprises reacting phenylacetaldehyde and N,N'-trimethyleneurea at a temperature between 15 and 220 C., in the presence of acid, and subsequently distilling N-(fi-phenylvinyl)-N,N-trimethyleneurea.

15. A method which comprises reacting capric aldehyde and N,N'-trimethyleneurea at a temperature between 15 and 220 C., in the presence of acid, and subsequently distilling N-(B-octylvinyl)-N,N-trimethyleneurea.

No references cited. 

1. A METHOD FOR PRODUCING AN N-VINYL DERIVATIVE OF A CYCLIC N,N''-ALKYLENEUREA WHICH COMPRISES REACTING, IN THE PRESENCE OF AN ACID, AN ALDHEYDE HAVING THE STRUCTURE OF FORMULA II: 